When networks for communications are created, they are usually designed for use with existing standards and protocols in mind. Significant investment may have been made to deploy an existing network. Accordingly, it is often commercially impractical to replace an entire network or large portions of an existing network that remains operational. The existing telephone network, also known as the PSTN, is an example of an existing functional network that remains functional, is large, and represents a huge investment in equipment. Unfortunately, in many situations desired enhancements to existing networks, e.g., the PSTN, such as some multicast services or web based services utilize resources that are beyond the capabilities of the network as it was originally designed. It would be desirable if a way could be found to add new functionality to the PSTN without requiring major modifications to the existing network and/or previously deployed equipment.
As new generations of service control technologies are becoming available, resulting in non-SS7 (non-Signaling System 7) based networks, many based on computer industry and Internet standards, interoperation and integration with established SS7 networks such as the PSTN is a significant problem which needs to be addressed.
Two commonly discussed methods of accessing these next generation control platforms from within the PSTN include 1) enhancements to PSTN control platforms, e.g., upgrades to service control points (SCPs), and 2) gateways to new SS7 domains, e.g., IP feature server behind a gateway that acts as an SS7 Service Switching Point (SSP). Each of these methods require significant new investment in the PSTN such as upgrading SCP systems, along with ongoing administrative costs such as provisioning new point codes and updating routing tables. Both methods are also limited in their utility, as they will normally be limited to acting on requests that are specifically made to an external control platform. Given the shortcomings of the above techniques, there is a need for additional network integration approaches that can provide greater flexibility and thereby allow for new services or better execution of existing services in addition to supporting interoperation of different networks.
In addition to a need to support network interoperability, there is a need for improved methods of supporting SCP load balancing to reduce the need to replace or upgrade existing SCPs as new services and/or more customers subscribe to advanced services in a given service region. Existing telephone services can be negatively affected when an SCP that provides advanced telephone services is used to capacity. Without load sharing, overloading of an SCP may occur while other SCPs that can provide the same services are under utilized, e.g., because of differences in regional customer demographics. There is a desire to alleviate this type of network congestion to provide better service to customers and to optimize the use of already deployed hardware.
From the above discussion it is apparent that there is a need to link the existing legacy (PSTN/SS7 network) with new external control platforms, e.g., IP based systems, existing in non-SS7 domains, to allow new services and/or enhanced services to be provided to PSTN users. The links to the new control platforms should, preferably, be performed in a manner that allows such external control platforms to interact with PSTN elements in a relatively transparent manner that does not require major modifications to existing PSTN elements. If this can be achieved, large additional investments in PSTN/SS7 upgrades and/or administration costs can be reduced or avoided while still allowing for new or enhanced services.
In view of the above discussion, it is apparent that there is a need for new methods of supporting PSTN system interoperability with non-SS7 based systems or networks, a need for a method of providing new services without requiring significant changes to already deployed SCPs and SSPs, and for improving SCP load balancing.